Hydroxyapatite: Preparation and properties

Larsen, S.; Widdowson, A. E.

doi:10.1007/bf02137328

Cited by 10 publications

(5 citation statements)

References 8 publications

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“…The ratio of Ca/P molar obtained is 1.98 and that the product obtained was calcium-rich HA. This value according to the literature 13 , HA compounds will form at a Ca/P ratio of about 1.2-2.0. In the calcium content, the increased concentration of carbonate in the mixing reaction causes the absorption of phosphate ions to be inhibited so that the ratio of Ca/P increases.…”

Section: Analysis Of Functional Groups Of Ha/col/chisupporting

confidence: 53%

SYNTHESIS AND CHARACTERIZATION OF HYDROXYAPATITE-COLLAGEN-CHITOSAN (HA/Col/Chi) COMPOSITE BY USING EX-SITU WET PRECIPITATION METHOD

2017

RJC

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Hydroxyapatite (HA) was included mineral of apatite is a bioactive ceramic material and biocompatible, which has similarity with the nature of the bone chemical structure. The synthesis of hydroxyapatite (HA) by using wet precipitation method consists of calcination, hydration, HA synthesizes, and thermal treatment. The solution 0.3 M (NH4)2.HPO4 was dropped on the suspension of 0.5 M Ca(OH)2 from tutut (Bellamya javanica) shells. While collagen is extracted from the waste fish (Later calcarifer) scales by the following acid and alkali extraction methods. Synthesis of HA/Col/Chi composite by using ex-situ wet precipitation method that has been formed from 2 ml collagen of 2%, 2 ml chitosan of 2% mixed with 2 gram of HA powder was dissolved in 20 ml of an ethanol solution at room temperature. The spectrum of HA/Col/Chi composite by FTIR showed the presence of functional groups of HA, collagen, chitosan, and indicate the presence of molecular interactions between -OH, -COOH, -NH2 on collagen chains and -OH, -NH2 on chitosan, and there is an interaction between HA, amide I, and amide II in collagen. X-Ray Diffraction Analysis of HA/Col/Chi composite showed the single phase of HA. Analysis element components of HA showed that the Ca/P ratio obtained is 1.98. In the HA analysis by scanning electron microscopy showed the formation of HA in the presence of agglomeration and has an irregular shape. In addition, has a size of 2.76 -6.48 µm.

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Section: Analysis Of Functional Groups Of Ha/col/chisupporting

confidence: 53%

SYNTHESIS AND CHARACTERIZATION OF HYDROXYAPATITE-COLLAGEN-CHITOSAN (HA/Col/Chi) COMPOSITE BY USING EX-SITU WET PRECIPITATION METHOD

2017

RJC

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“…X-ray diffraction identified no other minerals in the HA sample (data not shown); but, impurities in HA may have resulted in higher P concentrations relative to Ca concentrations. Greater than expected Ca/P ratios (1.85 to 2.58) characterized synthesized HA dissolved in water, which may result from excess Ca near the surface of HA crystals (Larsen and Widdowson, 1971). In an experiment to measure HA solubility, both Ca and P decreased over time from 17 to 120 d (Wier et al, 1971), again suggesting that long reaction times are necessary to reach an equilibrium in the HA system.…”

Section: Resultsmentioning

confidence: 94%

Factors Influencing the Effectiveness and Stability of Aqueous Lead Immobilization by Hydroxyapatite

Qiying

1996

J. environ. qual.

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The effects of Ca, K, Na, calcite, and EDT A on Pb immobilization by hydroxyapatite [CaIO(P04)6(OHh; HAl were investigated. The stability of hydroxy pyromorphite [PbIO(P04MOHh; HPJ (a reaction product of HA with Pb) and the effectiveness of using HA to immobilize Pb in Pb-contaminated soils also were examined. Neither Na nor K affected Pb immobilization. Aqueous Ca and calcite slightly inhibited Pb immobilization, but HA still reduced aqueous Pb > 97% in the presence of these species; however, EDTA significantly reduced the effectiveness of HA to immobilize Pb from Pb-EDTA solutions, with only 24 to 31 % resultant reduction in aqueous Pb. Hydroxypyromorphite was stable in the presence of HA up to 8 wk. Both higher Ca and lower P concentrations (following P removal by anion exchange resin) dissolved HP from a mixture of HA and HP, but the final aqueous Pb concentrations remained low «168 nmol L-I). High EDT A concentrations dissolved most (>85%) of the Pb from the same mixture. Hydroxyapatite effectively immobilized >71 % of the aqueous Ph in four PbHAs04 contaminated soils. The effectiveness of HA to immobilize aqueous Ph in the presence ofCa, K, Na, and calcite, and to immobilize aqueous Pb from Pb-contaminated soil .. , together with the stability of HP in the presence of high Ca and low P concentrations support our previous conclusion that HA has the potential to treat Ph contaminated water, soils, and wastes and that such a treatment can result in long-term in situ Pb stabilization; however, HA did not effectively immobilize Pb, nor was HP, stable in the presence of high EDTA concentrations. Thus, HA treatment will be ineffective in EDTA rich environments.

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“…Figure 4a. shows the energy dispersive x-ray spectroscopy (EDX) of HA which confirms the presence of HA with Ca/P ratio found to be 1.65 as the Ca/P mole ratio for HA could vary from 1.2-2.0 (Larsen and Widdowson, 1971). Figure 3b shows the TEM image of HA particles synthesised by microwave irradiation.…”

Section: Transmission Electron Microscopic (Tem) Analysismentioning

confidence: 53%

Synthesis and characterisation of nanocrystalline hydroxyapatite from sea shells

Santhosh

Prabu

2012

IJBNN

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Nanocrystalline hydroxyapatite was synthesised by wet chemical reaction between sea shells (CaCO 3 ) which were thermally converted to amorphous calcium oxide (CaO) and then to calcium hydroxide (Ca(OH) 2 ) and reacted with phosphoric acid (H 3 PO 4 ). Two experiments were conducted using wet chemical synthesis method. Hydroxyapatite (HA) was synthesised by slow addition of phosphoric acid in to calcium hydroxide (Ca(OH) 2 ) without microwave irradiation and in another method; microwave irradiation was carried out after the reactants were combined in a similar manner. In both the experiments, the Ca:P ratio of 1.67 was maintained. pH of the solution was maintained at 9 to avoid the formation of calcium deficient apatites. The synthesised samples show XRD patterns corresponding to hydroxyapatite. The wet chemical process without microwave irradiation resulted in rod shaped HA particles of size 101 nm, whereas microwave irradiation of the solution after reaction also resulted in rod shaped HA but the particle size was only 68 nm as evidenced from XRD analyses. The TEM analyses reveal average aspect ratios of 3.37 ± 1.28 and 5.98 ± 2.28 for methods without and with microwave irradiation respectively.

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Hydroxyapatite: Preparation and properties

Cited by 10 publications

References 8 publications

SYNTHESIS AND CHARACTERIZATION OF HYDROXYAPATITE-COLLAGEN-CHITOSAN (HA/Col/Chi) COMPOSITE BY USING EX-SITU WET PRECIPITATION METHOD

SYNTHESIS AND CHARACTERIZATION OF HYDROXYAPATITE-COLLAGEN-CHITOSAN (HA/Col/Chi) COMPOSITE BY USING EX-SITU WET PRECIPITATION METHOD

Factors Influencing the Effectiveness and Stability of Aqueous Lead Immobilization by Hydroxyapatite

Synthesis and characterisation of nanocrystalline hydroxyapatite from sea shells

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